Comparative genomics of bidirectional gene pairs and its implications for the evolution of a transcriptional regulation system
Comparative genomics of bidirectional gene pairs and its implications for the evolution of a transcriptional regulation system
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DOI：
10.1016/j.gene.2005.04.027
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发表时间：
2005-07-04
期刊：
影响因子：
3.5
通讯作者：
Imanishi, T
中科院分区：
文献类型：
--
作者：
Koyanagi, KO;Hagiwara, M;Imanishi, T
人们认为人类基因组中基因的排列不像原核生物那样有序，因为在许多情况下，基因似乎是随机分布在基因组中的。然而，最近有人通过关注位置紧密相邻的基因对，认为双向基因对在人类基因组中富集，而且这些基因对往往通过共享启动子序列而共同表达。我们将人类基因组中发现的这种偏向性组织结构与其他九种真核生物基因组中的这种偏向性组织结构进行了比较，利用总共 122,945 个相邻基因对揭示了这种偏向性组织结构是何时以及如何演变而来的。结果我们发现，这种偏向组织只存在于哺乳动物中，其他真核生物中并没有发现。有趣的是，我们发现这些双向排列的基因中有许多并不是哺乳动物特有的基因，而是各种动物中的保守基因。进一步的分析表明，这些基因对的双向排列是通过利用哺乳动物最近的血统中已经存在的基因而产生的，不会早于脊椎动物-蛙类的分化时期。由于新的双向排列可能导致新的共同调控转录，我们的研究结果提供了证据，说明转录调控系统是如何通过基因组组织的变化而进化的，尤其是在人类的前身中。(c) 2005 Elsevier B.V. 版权所有。保留所有权利。
Arrangement of genes in the human genome was not considered to be ordered like those of prokaryotes, as in many cases genes appeared to be randomly distributed across the genome. However, by focusing on the closely located adjacent gene pairs, it was recently suggested that the bidirectional pairs were enriched in the human genome and these pairs tended to be coexpressed by sharing promoter sequences. We compared this biased organization found in the human genome with those in the genomes of nine other eukaryotes to reveal when and how the biased organization had evolved using a total of 122,945 adjacent gene pairs. As a result, we found that the biased organization was found only in mammals, and not in other eukaryotes. Interestingly, we found that many of these genes in the bidirectional arrangement were not mammalian specific genes but conserved among various animals. Further analyses revealed that the bidirectional arrangement of these pairs had arisen by utilizing already-existing genes in the lineage leading to mammals recently, no earlier than the vertebrate-ascidian divergence. Since the novel bidirectional arrangement could result in novel co-regulated transcription, our results here provide evidence that shows how a transcriptional regulation system has evolved through changes in the genome organization, especially in the lineage leading to humans. (c) 2005 Elsevier B.V. All rights reserved.